1. Field of the Invention
This invention generally relates to the field of wireless communications. More particularly, the present invention relates to determining configuration options of a wireless communications link employing a network model operation of a mobile terminal machine.
2. Description of Background Information
Wireless communication systems are widely deployed to provide various types of communication such as voice, data, and so on. These systems may be based on code division multiple access (CDMA), time division multiple access (TDMA), or some other modulation techniques. A CDMA system provides certain advantages over other types of systems, including increased system capacity.
A CDMA system may be designed to support one or more CDMA standards such as (1) the “TIA/EIA-95-B Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System” (the IS-95 standard), (2) the standard offered by a consortium named “3rd Generation Partnership Project” (3GPP) and embodied in a set of documents including Document Nos. 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214 (the W-CDMA standard), (3) the standard offered by a consortium named “3rd Generation Partnership Project 2” (3GPP2) and embodied in a set of documents including “C.S0002-A Physical Layer Standard for cdma2000 Spread Spectrum Systems,” the “C.S0005-A Upper Layer (Layer 3) Signaling Standard for cdma2000 Spread Spectrum Systems,” and the “C.S0024 cdma2000 High Rate Packet Data Air Interface Specification” (the cdma2000 standard), and (4) some other standards.
Recent innovations in wireless communication and computer-related technologies, as well as the unprecedented growth of Internet subscribers, have paved the way for mobile computing. In fact, the popularity of mobile computing has placed greater demands on the current Internet infrastructure to provide mobile users with more support. CDMA technology is a crucial part of meeting these demands and providing users with the necessary support.
Wireless communication systems employing this technology assign a unique code to communication signals and spread these communication signals across a common (wideband) spread spectrum bandwidth. As long as the receiving machine in a CDMA system has the correct code, it can successfully detect and select its communication signal from the other signals concurrently transmitted over the same frequency band. The use of CDMA produces an increase in system traffic capacity, improves overall call quality and noise reduction, and provides a reliable transport mechanism for data service traffic.
FIG. 1 illustrates the basic elements of such a wireless data communication system 100. Artisans of ordinary skill will readily appreciate that these elements, and their interfaces, may be modified, augmented, or subjected to various standards, without limiting their scope or function. System 100 allows a mobile terminal equipment, TE2 device 102 (Terminal Equipment 2, a data terminal that provides a non-ISDN user-network interface, such as a laptop or palmtop computer), to communicate with an Interworking Function (IWF) 108. (In CDMA2000, the relevant data standards are IS707A and IS835. In IS835, the IWF is replaced by the PDSN (Packet Date Serving Node). For purposes of discussion, IWF 108 as used hereafter shall refer to both IWF and PDSN.
System 100 includes a wireless communication device, MT2 device 104 (Mobile Terminal 2, a mobile station termination that provides a non-ISDN user-network interface, such as a wireless telephone), and a Base Station/Mobile Switching Center (BS/MSC) 106. IWF 108, for example, supports data calls and serves as a gateway between the wireless network and other networks, such as the Public Switched Telephone Network or wireline packet data networks providing Internet- or Intranet- based access.
As illustrated in FIG. 1, IWF 108 is coupled to BS/MSC 106 via the L interface. (In IS835, the L interface is more generally referred to as the R-P link or the A-interface.)
Often IWF 108 will be co-located with BS/MSC 106. TE2 device 102 is electronically coupled to MT2 device 104 via the Rm interface. MT2 device 104 communicates with BS/MSC 106 via the wireless interface Um. TE2 device 102 and MT2 device 104 may be integrated into a single unit or may be separated out, as in the case of an installed mobile phone unit in which a laptop is TE2 device 102 while the transceiver is MT2 device 104. The combination of TE2 device 102 and MT2 device 104, whether integrated or separate, is generally referred to as a mobile station (MS) 103.
Other support is made possible by applying various protocols to control, manage, or otherwise facilitate different aspects of wireless communications. For example, the Internet Protocol (IP) has been incorporated in wireless communications to accommodate packet-oriented services. The IP protocol specifies the addressing and routing of packets (datagrams) between host computers, and is defined in Request For Comment 791 (RFC 791) entitled, “INTERNET PROTOCOL DARPA INTERNET PROGRAM PROTOCOL SPECIFICATION,” published in September 1981.
The IP protocol is a network layer protocol that encapsulates data into IP packets for transmission. Addressing information is part of the header of the packet. IP headers (e.g., IP version 4) contain 32-bit addresses that identify the sending and receiving hosts. These addresses are used by intermediate routers to select a path through the network for the packet towards its ultimate destination at the intended address. Then, the IP protocol allows packets originating at any Internet node in the world to be routed to any other Internet node in the world, given that the originating party knows the IP address of the destination party. This also applies to the Internet Protocol version 6 (IPv6) the only difference being that IPv6 employs 128 bit addresses, and has other optimizations to air in routing.
Another protocol incorporated in wireless communication systems is the Point-to-Point Protocol (PPP) protocol, which provides, inter alia, Internet access. The PPP protocol is described in Request for Comments 1661 (RFC 1661), entitled “THE POINT-TO-POINT PROTOCOL (PPP),” published in July 1994.
For example, the PPP protocol specifies a method for transporting multi-protocol datagrams over point-to-point links and contains three components: a Link Control Protocol (LCP) for establishing, testing, configuring, and maintaining a data link connection; a family of Network Control Protocols (NCPs) for establishing and configuring different network-layer protocols; and encapsulating multi-protocol datagrams over serial links.
In an effort to provide a host of services on wireless communication systems, various standards have been developed to accommodate the wireless data transmission between TE2 device 102 and IWF 108. For example, the TIA/EIA IS-707.5 standard, entitled “DATA SERVICE OPTIONS FOR WIDEBAND SPREAD SPECTRUM SYSTEMS: PACKET DATA SERVICES,” published in February 1998, defines requirements for support of packet data transmission capability on TIA/EIA IS-95 systems and specifies a suite of packet data bearer services. Also, the TIA/EIA IS-707-A.5 standard, entitled “DATA SERVICE OPTIONS FOR SPREAD SPECTRUM SYSTEMS: PACKET DATA SERVICES,” and the TIA/EIA IS-707-A.9 standard, entitled “DATA SERVICE OPTIONS FOR SPREAD SPECTRUM SYSTEMS: HIGH-SPEED PACKET DATA SERVICES,” both published in March 1999, define requirements for packet data transmission support on TIA/EIA IS-95 and CDMA2000/IS-2000 systems.
These standards provide certain packet data service options that may be used to communicate between TE2 device 102 and IWF 108 via BS/MSC 106. In doing so, IS-707.5 introduces the Network Model, which details the packet data protocol requirements for the Rm and Um interfaces. Under this model, two separate PPP links are provided at the data link layer: a first PPP link (PPPR) provides the data link layer between TE2 device 102 and MT2 device 104 (i.e., across the Rm interface), and a second PPP link (PPPu), independent of the first, provides the data link layer between MT2 device 104 and IWF 108 (i.e., across the Um and L interfaces).
The separate and independent PPP links help support “transparent mobility;” that is, TE2 device 102 should experience seamless and transparent service, regardless of time and its current IWF 108 point-of-attachment. As such, TE2 device 102 remains unaffected by location changes, such as PPP renegotiations occurring on the Um link, such as when MT2 device 104 attempts to attach to a different IWF 108. Thus, the Network Model operates to isolate the PPPR link from the PPPU link to prevent changes on the Um link from affecting the Rm link. In other words, the PPPU link may be renegotiated, inter alia, without forcing the PPPR link to renegotiate.
FIG. 2 illustrates the protocol stacks in each entity of the IS-707.5 Network Model. At the far left of FIG. 2 is a protocol stack, shown in conventional vertical format, depicting the protocol layers running on TE2 device 102 (e.g., the mobile terminal, laptop or palmtop computer). TE2 device 102 protocol stack is illustrated as coupled to MT2 device 104 protocol stack via the Rm interface. MT2 device 104 is illustrated as coupled to BS/MSC 106 protocol stack via the Um interface. BS/MSC 106 protocol stack is, in turn, illustrated as coupled to IWF 108 protocol stack via the L interface.
By way of example, the protocols depicted in FIG. 2, operate as follows: a PPP layer on TE2 102 device associated with the Rm interface (i.e., PPPR 208) encodes (e.g., frames) packets of an upper layer protocol 204, and a network layer IP protocol 206. PPPR protocol 208 then transmits the packets across the Rm interface, for example, using a TIA/EIA 232-F layer protocol 210 to a TIA/EIA-232-F layer protocol 212 on MT2 device 104. The TIA/EIA-232-F standard is defined in “INTERFACE BETWEEN DATA TERMINAL EQUIPMENT AND DATA CIRCUIT-TERMINATING EQUIPMENT EMPLOYING SERIAL BINARY DATA INTERCHANGE,” published in October 1997. Other standards or protocols may also be used to define the transmission across the Rm interface. For example, other applicable Rm interface standards may include, the “UNIVERSAL SERIAL BUS (USB) SPECIFICATION, Revision 1.1,” published in September 1998, and the “BLUETOOTH SPECIFICATION VERSION 1.0A CORE,” published in July 1999.
TIA/EIA 232-F protocol 212 on MT2 device 104 receives the packets from TE2 device 102 and passes them to a PPPR layer 213 of MT2 device 104. PPPR layer 213 unframes the packets within the PPP frames and, when a data connection is established, may transfer the packets to a PPP layer associated with the Um interface (e.g., PPPU protocol 217). PPPU layer 217 re-frames the packets for transmission to a PPPU peer located in IWF 108. A Radio Link Protocol (RLP) layer 216 and an IS-95 layer protocol 214, both of which are well known in the art, may be used to transmit the packet-encapsulated PPP frames to BS/MSC 106 over the Um interface. RLP layer protocol 216 is defined in the IS-707.2 standard, entitled “DATA SERVICE OPTIONS FOR WIDEBAND SPREAD SPECTRUM SYSTEMS: RADIO LINK PROTOCOL,” published in February 1998, and also in the IS-707-A.2 standard, entitled “DATA SERVICE OPTIONS FOR SPREAD SPECTRUM SYSTEMS: RADIO LINK PROTOCOL,” published in March 1999.
A RLP layer protocol 222 and an IS-95 layer protocol 220 in BS/MSC 106 transfer the packets to a relay layer protocol 224 for transmission across the L interface to a relay layer protocol 234 on IWF 108. PPPU layer 232 then un-frames the received packets and transfers them to a network layer protocol IP 230, which in turn passes them to a upper layer protocol 228 or forwards them to the their final destination. As stated above, PPPR layer protocol 213 may transfer the packets to PPPU layer protocol 217 when a data link connection is established. RFC 1661 provides that Link Control Protocol (LCP) packets may be exchanged and negotiated over each PPP link (i.e., PPPR and PPPU) to establish, configure, and test the data link connection, as illustrated in FIG. 3. Once the LCP packets (see flow arrows (1A) and (1B) of FIG. 3) are exchanged, the link options negotiated, and the data link connection established, a network layer connection may be established between TE2 device 102 and IWF 108. In FIG. 2, network layer protocols 206, 215, 218, 230 (i.e., the IP layer protocols) use the Internet Protocol Control Protocol (IPCP) (see flow arrow (2) of FIG. 3) to negotiate the IP protocol on the PPP links to achieve the end-to-end connection between TE2 device 102 and IWF 108. IPCP is a part of a family of Network Control Protocols (NCPs) that are part of the PPP protocol, and is described in Request for Comment (RFC) 1332, “THE PPP INTERNET PROTOCOL CONTROL PROTOCOL (IPCP),” published in May 1992. When the system supports IPv6, IPCPv6 may also be negotiated, it is described in RFC 2472.
IPCP utilizes configuration request messages to negotiate various configuration options. One such option is the IP Compression Protocol Option. When enabled, this option generally employs the Van Jacobson compression methodology for compressing the TCP/IP headers in a PPP packet. The Van Jacobson compression methodology improves the efficiency of a protocol by reducing the overhead in the packet headers, and is described in RFC 1144 entitled, “COMPRESSING TCP/IP HEADERS FOR LOW-SPEED SERIAL LINKS,” published in February 1990. The negotiation of the IP compression protocol option uses a specification of a maximum compression slot ID field, used to determine the maximum number of compression and decompression slots for a particular PPP link. As stated above for the IS-707.5 Network Model, the PPPU link may be renegotiated without forcing the PPPR link to renegotiate. During an initial call set-up, the LCP and IPCP mechanisms negotiate to establish identical configuration options for both the Um and Rm interfaces. As long as the configuration options remain identical, all of the PPP data packets (see flow arrow (3) of FIG. 3) may “pass through” from one interface to the other without MT2 device 104 examining the packets.
Presently, however, MT2 device 104 examines the contents of each and every packet to determine the configuration options. In cases where the configuration options remain identical, however, such examination is unnecessary, as it adversely affects the processing resources and throughput latency of MT2 device 104.